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The Equal Earth, an equal-area projection, and the Peirce quincuncial, a conformal projection, are now available in ArcGIS 10.7 and ArcGIS Pro 2.3.

 

The Equal Earth is an equal-area pseudocylindrical projection for world maps. It shows a pleasant appearance of the land features and its shape is similar to the well-known Robinson projection. The projection is appropriate for mapping global phenomena or for any other thematic world map that requires areas at their true relative sizes. It was jointly developed by Tom Patterson (US National Park Service, ret.), Bernhard Jenny (Monash University) and Bojan Šavrič (Esri) in 2018. It was published in IJGIS. Some behind-the-scenes look at how (and why!) it was created can also be found in ArcUser article.

 

The Equal Earth map projection

 

Equal Earth in use:

Political and physical wall maps by Tom Patterson
The Living Land by Esri Story Maps team

40 Years of Nautical Piracy by John Nelson

 

 

The Peirce quincuncial map projection shows the world in a square. The projection is conformal except in the middle of the four sides of the square. It was developed by Charles S. Peirce in 1879. In his original design, the projection is centered at the North Pole, which displays the equator as a square rotated relative to the projection edge. The original implementation was on a sphere. Esri's implementation of this projection maintains its conformal properties on ellipsoids also such as WGS 1984. The projection can be tessellated or mosaicked.

 

The Peirce quincuncial projection shown in square and diamond orientations.

 

Happy projecting! 

 

 

Cover photo by John Nelson

ArcGIS 10.4 now supports eight small-scale map projections displayed in an animated gif:

Compact Miller
Patterson
Natural Earth
Natural Earth II
Wagner IV
Wagner V
Wagner VII
Eckert-Greifendorff

 

The Eckert-Greifendorff, Wagner IV and Wagner VII are equal-area projections; the remaining five are compromise projections that try to minimize overall distortion. Sample definitions for the first seven projections are available in the Projected Coordinate Systems\World  and Projected Coordinate Systems\World(Sphere-based) folders.

 

The Eckert-Greifendorff, Wagner IV and Wagner VII also support ellipsoidal equations. Gnomonic, quartic authalic and Hammer projections are now available in ellipsoidal forms too.

 

With Eckert-Greifendorff, Hammer ellipsoidal, quartic authalic ellipsoidal, Wagner IV, and Wagner VII, one can select a custom central latitude and create oblique aspects of the projections.

New-Projections-ArcGIS-10.4.gif

ArcGIS 10.4 includes three variants of polar stereographic projection (variant A, B and C – EPSG codes 9810, 9829 and 9830 respectively) and two new variants of Mercator projection (variant A and C – EPSG codes 9804 and 1044 respectively). Mercator variant B (EPSG code 9805) was already included before as Mercator projection.

 

Mercator variants A and B have origin of northings / Y values at the equator. Variant A uses a scale factor at the equator to reduce overall scale distortion and effectively defines two standard parallels that are symmetric around the equator. Variant B takes a standard parallel and effectively forces the scale factor at the equator to be less than one. Variant C is similar to variant B, but with the addition of a latitude of origin. The origin of northings / Y values occurs at the latitude of origin.

 

The polar stereographic variant A is centered at a pole. The longitude of origin defines which longitude will be going straight “down” from the North Pole or “up” from the “South Pole” towards the middle of the map. A scale factor reduces the overall scale distortion and effectively defines a standard parallel. The variant B is similar to variant A, only that it takes a standard parallel to reduce the overall scale distortion of the projection and results in a scale factor at the pole of less than one. Variant C is similar to variant B, but with the addition of a latitude of origin. The origin of northings / Y values occurs at the intersection of the latitude of origin and the longitude of origin.